Problem: A goblet contains $5$ red balls, $5$ green balls, and $9$ blue balls. If a ball is randomly chosen, what is the probability that it is not blue?
There are $5 + 5 + 9 = 19$ balls in the goblet. There are $9$ blue balls. That means $19 - 9 = 10$ are not blue. The probability is $ \frac{10}{19}$.